Jammed CH pump - ideas to free it?

[d...@gglz.com]

Hiya - switching CH back on for the first time this Autumn.

Pump is Grundfos SuperSelectric 15-60.

I've checked there's volts on the pump.

Manufacturers data says, take out the screw plug on top of the pump
body, then press in and twiddle the rotor with a 3mm screwdriver.

Tried that - rotor locked absolutely solid.

Checked the identical pump in the system - and that moves easily.

So - ideas to try next?

Brute force?

Strip part of the pump?

Don't bother and buy another?

[Jim K]

<whisper> wd40? </whisper>

Jim K

[Spamlet]

<d...@gglz.com> wrote in message
news:fc60717d-fc4b-4abe...@e14g2000yqe.googlegroups.com...

> Hiya - switching CH back on for the first time this Autumn.
>
> Pump is Grundfos SuperSelectric 15-60.
>
> I've checked there's volts on the pump.
>
> Manufacturers data says, take out the screw plug on top of the pump
> body, then press in and twiddle the rotor with a 3mm screwdriver.
>
> Tried that - rotor locked absolutely solid.
>
> Checked the identical pump in the system - and that moves easily.
>
> So - ideas to try next?
>
> Brute force?

In several systems I've dealt with, the pump gets stuck every year. This
was with pumps in the vertical position so the spindle itself is horizontal
and tends to move toward the cover cap and then get slightly glued in place
by precipitation. Generally with the motor on, all you need to do is take
tha cap off, find a soft (a pencil or dowel) drift and give the centre of
the spindle a smart tap and the impeller will move back and start turning.
Then you run the pump of fairly high speed until water starts to flow from
the cap hole and put the cap back on. Sometimes, if the impeller is
particularly prone to ride up, I have whittled a nylon plug to hold it back
a bit.

A word of warning - not sure if it applies to all - one pump spindle had a
tempting 'cross head' screw impression on it, but it *isn't for turning* and
it is *ceramic* the spindle is thus very easy to splinter with a
screwdriver. But a smart tap with something less hard gets it running
nearly every time. Hundreds of Grunfoss pumps must get thrown away this
time every year when all they need is a smart tap on the spindle, if my
experience is anything to go by.
>

S

[Mike Harrison]

Definitely worth stripping before resorting to replacement

[d...@gglz.com]

> Generally with the motor on, all you need to do is take
> tha cap off, find a soft (a pencil or dowel) drift and give the centre of
> the spindle a smart tap and the impeller will move back and start turning.

Fantastic! Worked first time.

That's a TOP TIP. Deserves to go in the wiki somewhere.

[Andy Cap]

I changed a couple of pumps before realising the problem was that the
shaft was horizontal. It is fitted into a horizontal length of pipe and
since repositioning the pump, so that the shaft is pointing down at 45
degrees, it's run for many years, with no further problems.

Andy C

[Dave Liquorice]

On Tue, 28 Sep 2010 08:12:10 +0100, Andy Cap wrote:

> I changed a couple of pumps before realising the problem was that the
> shaft was horizontal.

IIRC the destructions for the Grudfoss circulators they do say not to
install with the shaft axis horizontal or with the motor unit lower
than the pipework. I have two here, in vertical pipe runs, never
given a problem but then they don't sit unused for months on end
during the summer, even the CH one only gets a few weeks rest if
that. Which reminds me I haven't excercised the gate valves for a
while...

--
Cheers
Dave.

[Michael Chare]

"Dave Liquorice" <allsortsn...@howhill.com> wrote in message
news:nyyfbegfubjuvyypb...@srv1.howhill.co.uk...

Well mine has not got stuck recently, not sure if that is because the axis
is now no longer horizontal or I converted to a fully pumped system!

--
Michael Chare

[Spamlet]

<d...@gglz.com> wrote in message
news:f8010aec-91a8-4792...@g18g2000vbn.googlegroups.com...

YW.

In fact, if you strip a spare pump down, you'll see there isn't much inside
to go wrong, and one just comes a cropper by not realising how brittle the
spindle is, and taking appropriate care.

I once had one where the impeller veins became filled up with little
polystyrene beads from some old ceiling tiles that had been used to cover
the header tank. Otherwise, what usually seems like a pump problem - rads
not getting evenly warm quickly - turns out to be a three port valve
problem, not allowing the full flow from the pump through the CH part of the
system. That is probably the second most common reason for pumps being
changed unnecessarily.

Cheers,

S